"It's very cautionary and conservative," Sandberg said. "He's felt something the last few weeks. He just wanted to get peace of mind about it. He was still able to pitch and could still pitch now. But it was a precautionary move now to get him checked out."

Kendrick is 3-9 with a 6.45 ERA in 14 starts from June 30 through Friday's start against the Nationals. Kendrick is eligible for salary arbitration following the season, so this recent run has not come at a good time.

Asked if Kendrick could be shut down the remainder of the season, Sandberg said, "Unsure about that. … His velocity was still good. He was still able to throw a number of pitches and still pitch with it. It wasn't a thing that was a concern the last few weeks. At this stage of the season, the organization just felt for his peace of mind, to be checked out."

Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.